The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

hi Rick, sorry for the delay......i haven't had chance to do anything further with the radio as yet. as soon as i do, i will let you know how i get on.

thanks again.
rick.

hi Rick, the bad capacitor was C235 directly in front of TR51 i first changed TR51 then driver checking for shorts as i went. i reset the bias as you discribed...before i fitted the final i powered up the radio to see if the driver was functioning and it checked out with my other radio so i proceede...

hi Rick, there was a short on a capacitor just in front of TR51 which must have caused the problem so again i have changed all the components just to be sure... checking for shorts after every step,i weren't getting any readings on the meter, none were found! The capacitor TR50 TR51 DRIVE FINAL are ...

hi Rick, i changed the the regulator and the drive transistor and without the final in circuit i powered on the radio, immediately it blew the regulator in half (the transistor i used was a TIP32c which i was told this was an suitable replacement) the one it replaced was a BDX54C is this an higher p...

Hi rick im going to replace all four components as you recommended. however as you can probably sense, i have very limited experience so please be patient.. i can change the components but how do i reset the bias and how will i know if thers a short on the drive and final, what should i expect to se...

ive done as you said Rick, took out the test board and powered on no problem. the voltage at TR50 reads: lead 1= 5.49v lead 2= 0 lead 3= 5.64v is this as it should be? is it what you thought and if so is it just a matter of replacing the driver and final or should i do further checks before hand? mu...

SOUNDS LIKE YOU HAVE EXACTLY THE SAME PROBLEM..

MAYBE I'LL JUST PUT IT BACK IN THE CUPBOARD.

THANKS FOR YOUR REPLY.

RICK.

I HAVE A COBRA 148GTLDX THAT WONT POWER ON. THE PROBLEM CAME FROM A VARIABLE POWER MOD THAT WENT WRONG! AFTER THE MOD THE RADIO SWITCHED ON, BUT WHEN THE OUTPUT POWER WAS INCREASED IT SHUT DOWN THE POWER SUPPLY AND WOULD NOT TURN BACK ON WHILE THE RADIO WAS STILL CONNECTED. I HAVE TRIED ANOTHER POWE...

it was a very small break in one of the traces.

thanks for your help.

appreciated.

Rick.

I HAVE A PRESIDENT GEORGE..WHEN POWERED UP ALL IT DOES IS SCANS THROUGH THE CHANNELS?? IT WONT STOP UNTIL I KEY THE MIC, THEN AFTER A FEW SECONDS IT FLICKS THROUGH CHANNELS AGAIN?? DOES ANYONE HAVE ANY IDEA WHY AND WHAT COULD CAUSE THIS? I AM TOTALLY STUCK....MY RADIO IS UNUSABLE! ALL HELP IS APPREC...

I have a cobra 148gtl dx, it worked fine and then nothing. doesn't light up or anything. power supply is fine, fuse is good, protection diode is good. what should i check next? what could cause this to happen? all help and suggestions are welcome...im going nuts without my radio!! the main pcb: PC-8...